Ember in Shadow — Melissa McShane

As a royal wedding draws near, relations between humans and dragons are better than ever. Even the discovery that an ancient, evil entity was behind the human animosity toward dragons cannot stop the dragon Lamprophyre and her human friend Prince Rokshan from feeling victorious. But the entity still exists, and its next attack targets Lamprophyre directly, using magic that no one alive has ever seen before. Virtually helpless and newly vulnerable to the entity's attacks, Lamprophyre must discover a way to stop an enemy she cannot see, whose minions lurk in every shadow, while searching for a way to reverse what the entity did to her. And time is running out. She has to be lucky all the time. Her enemy only has to be lucky once.